4142 H.T. Tool Steel

Chemical Analysis:
Carbon .38/.46
Manganese .70/1.70.
Phosphorus .035 Max.
Sulfur .040 Max.
Silicon .15/.35
Chromium .75/1.20
Vanadium .10 Max.
Tungsten -------
Molybdenum .15/.25
Cobalt -------
Tempering Temp. º(F): Hardness Rc
As-quenched 60.1
400 57.8
500 53.4
600 49.5
700 46.1
800 42.9
900 38.8
1000 34.1
1100 31.1
1200 27.7
1300 23.5

Uses:

Brake die, support tooling, die holders, short run stamping and bending dies.

Forging/Rolling:

Heat slowly and uniformly to a temperature of from 1750° F to 1850° F.  Cool slowly from the forging or rolling temperature.

Annealing:

Heat slowly to 1500° F, and hold for 1/2 hour per inch of thickness.  Furnace cool at 20° F per hour to 1230° F; air cool to room temperature.   Expected Brinell hardness 197 max.

Hardening:

4142 material is prehardened from the mill to a hardness of BHN 270/320 in thicknesses to 4" inclusive and BHN 260/310 in thicknesses over 4" to under 6" inclusive.  CAUTION: 4142 material must be annealed prior to rehardening treatment to obtain a higher hardness.  Heat treat the same as 4140.

Tempering:

No tempering is required, since the material is already prehardened at the mill.  If the material is rehardened to obtain a higher hardness, the above tempering table may be used as a guide.  Parts should be held a minimum of 1 hour per inch of thickness.  A single temper is sufficient.  However, since 1/2" dia. specimens were used for this test, it may be found that heavier sections are several points lower.